1. Field of the Invention
This invention pertains generally to anchoring systems in buildings or other structures, and more particularly to a linearly extendible impact anchor driving pole and anchor system for installing mechanical anchors for ceiling suspended structures.
2. Description of Related Art
The attachment of electrical conduits, panels, machines, cables, straps, supports and other fixtures to masonry or concrete building structures is typically accomplished with an anchor secured within a pre-drilled bore. The masonry anchors known in the art are normally one of three types: threaded, expansion or chemical adhesive. Threaded anchors are not often suitable for use in masonry or stone because the substrate material is too brittle or too hard to allow a threaded anchor piece to tap the sides of the bore to create corresponding threads to secure the anchor. As a consequence, the self-tapping anchor cannot withstand any applied load without failing and can damage the substrate.
Chemical adhesives alone or in combination with an anchor member may be deposited in the bore and allowed to cure to secure an anchor. However, even fast acting agents require 10 to 30 minutes to set before the application of a load or any further manipulation of the anchor. The strength of the adhesive interface with the sides of the bore can also weaken over time and tensile loading of the anchor.
Expansion or wedge anchors are adapted to be introduced into a pre-drilled bore and to engage the wall of the bore with various types of expanding members which press against the walls and these anchors can be exposed to a load immediately.
Strike or impact expansion type wedge anchors are often used to anchor fixtures to concrete ceiling and support structures. The typical impact wedge anchor has a cylindrical body and an expansion wedge at the distal end of the body that will cause the body elements or a sleeve to expand upon the application of tensile forces to the wedge. These types of wedge anchors are inserted into a pre-drilled hole with one or more impacts with a hammer and then set by causing the expanding members to wedge securely into the concrete, brick or other masonry material. Impacts with a hammer are required because the expansion sleeve or body must be frictionally engaged with the sides of the bore before the radial expansion by the frustoconical portion of the anchor with the application of a load. Therefore, the outside diameter of the sleeve must be approximately the same diameter as the inside diameter of the bore.
Other expansion anchors use interior threads within the body of the anchor and a threaded member with a wedge to radially expand the body or expansion sleeve against the walls of the bore to secure the anchor. Rotation of a nut on the threaded member draws the portions of the wedge through the expansion sleeve causing it to expand radially increasing the frictional engagement of the sleeve with the walls of the bore thereby securing the anchor and increasing the load capability of the anchor. The initial setting of the anchor is accomplished through the tightening of the nut rather than by tensile load forces pulling outwardly on the anchor with these types of anchors. Accordingly, bolt expandable body type anchors that require the installation of the body in the bore first by hammering and then expanded are installed in two stages.
Still other anchors, such as split drive anchors or strike nail anchors, are set in pre-drilled holes with multiple impacts causing direct expansion of the anchor body sections against the side walls of the bore. These types of anchors are installed in a single stage.
One common use for wedge anchors is with suspended ceilings that are often used in public buildings that comprise a grid like framework and removable ceiling tiles. The framework forming the ceiling is suspended by a series of supports, typically threaded rods, attached to anchors in the building structure. The threaded rod is normally coupled to a threaded member of the anchor with a long bodied nut or threaded sleeve. Installation of the anchor requires drilling of the hole, insertion of the anchor followed by multiple impacts to the anchor to set the anchor within the hole. The use of a wrench to tighten a nut may also be needed to complete the installation of the anchor. This will often require the installer to ascend and descend a ladder multiple times to perform each task or installation step and use several different tools.
In addition, use of a hammer at the top of a ladder on an overhead horizontal surface makes it difficult to strike the anchor squarely and is also physically demanding on the worker. Inaccurate strikes can result in the bending of the anchor or distortion of the threads that can lead to mechanical failure of the anchor. Improper alignment or damaged threads of the anchor may also require replacement of the anchor or limit the nature of the load that can be attached to the anchor.
Accordingly, there is a need for an apparatus and method for reducing the time and effort necessary for the installation of each support element and anchor to a stone or masonry structure. Reducing the amount of work required or the exposure to risk at a construction site can result in significant economic savings, greatly improved efficiency, lower accident rates and improved safety records. The present invention satisfies these needs as well as others and is generally an improvement over the art.